Tryptophan substitution mutants on S5 largely retain mechanosensitivity as quantified with Δα. (A) Similar recordings as in Fig. 3 of L382W and T391W showing representative tryptophan mutant channels whose saturation level can be determined at high [Ca²⁺] under high pressure. (B) Δα extracted from a similar plot as in Fig. 1 B and Fig. 3 F were compared among wild type and 10 different tryptophan mutants on S5 whose saturation level can be determined at high [Ca²⁺] under high pressure. See Materials and methods for the determination of the saturation level. None of the mutants show significantly reduced Δα, whereas F384W and F394W showed slightly increased Δα (between the wild type and 10 tryptophan mutants; P > 0.05 except for F384W and F394W). Means ± SD (n = 6 for wild type and n = 3 for each mutant).